PROXIMA HIP
The profile of the patient presenting for total hip replacement has changed. Pain and disability are no longer the only indications for surgery. The millennium patient, empowered with information, seeks surgical intervention to restore quality of life. Thus, even younger patients are presenting for total hip replacement. Conservative surgery embraces both soft issue sparing and bone conservation. If the surgeon is confident the hip he is going to use will outlast the patient he should use it. Otherwise he should consider the next operation and conserve bone.
Any implant that makes contact with the diaphyseal cortex or is ingrown distally will offload distally with consequent proximal stress protection. Bone conservation is achieved both by taking less bone at the time of surgery and by optimising the physiological loading of the proximal femur to preserve bone in the longer term.
Elegant biomechanical studies have shown that the PROXIMA is not a “fit and fill” prosthesis. Excellent axial and rotational stability can be achieved within the cancellous bone, and the implant is suspended in and moves in consort with the surrounding cancellous bone. This reduces the shear stresses at the fixation interface and optimizes load transfer in the metaphysis.
The technique for the insertion of the PROXIMA is ideally suited for minimally invasive surgical approaches. The “MicroHip” technique uses a section of the anterior Smith-Peterson approach. This is a truly internervous and intermuscular plane which provides excellent access to the hip joint. Minimal soft tissue disruption, together with bone preservation, makes PROXIMA a truly conservative option for the millennium patient. |
Post-operative radiograph of the same patient with PROXIMA Hip implant on left side |
ARTICULAR SURFACE REPLACEMENT
The aims of articular surface
The modern day patient is getting younger and more demanding. There is a premium on quality of life and desire and need to rapidly return to normal activities. The patients are looking for an implant that will allow them full function and let them perform their daily routine activities, without any concern. The modern day patient is looking for optimized function. Patients approaching joint replacement want to feel confident that their implant will last as long as possible.
The success of such a procedure relies on the use of:
- High performance bearings (articulation
between ball and socket)
- Clinically reliable implants
- Responsible and effective minimally
invasive techniques |
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Radiograph of a 33year old male patient with bilateral ankylosing spondylitis
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The advantages
Post op X-ray of 30 years old female patient who underwent ASR of Left Hip
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The advantages of articular surface replacement include reduced dislocation, restoration of “normal anatomy”, anatomical loading of the hip joint and preservation of the patient’s natural bone. There is a benefit from increased range in motion and superior restoration of joint function. By utilizing the advances in Metal-on-Metal technology the resurfacing procedure offers patients a very durable and long lasting implant that is well suited for higher demand activities and lifestyles.
The procedure
Articular surface replacement is similar to a traditional total hip replacement from a surgical perspective. In a resurfacing procedure the head is not removed but with the use of specially designed instruments the femoral head is precisely reshaped to receive the resurfacing implant.
The reshaped head is fitted with a metal ball, which is cemented on. The acetabulum (socket) is prepared in a similar fashion for both a traditional total hip replacement and resurfacing with a metal shell being firmly fitted into the acetabular bone. The bone will then grow into the shell to hold it in place. |
The risks
The risks associated with a resurfacing procedure are similar to a total hip replacement. In addition a resurfacing replacement may fail due to femoral neck fracture or softening of the bone (avascular necrosis). A revision procedure for a resurfacing implant is relatively simple as the head can be removed and it can be converted to a total hip, similar to a primary total hip procedure.
Hybrid THR
A hybrid THR has one component, usually the acetabular socket, inserted without cement, and the other component, usually the femoral stem, inserted with cement. This technique was introduced in the early 1980s, so long-term results are just now being measured. A hybrid hip takes advantage of the excellent track records of cementless hip sockets and cemented stems. |
